Generally, in odontotherapy, when taking an intraoral impression in a preparation stage of manufacturing prostheses, an impression material such as silicone impression materials, alginate impression materials, and the like is used. An impression tray is used to intraorally hold such an impression material. The impression material is applied on the impression tray that is inserted into an oral cavity of a patient, and after the impression material is pressed for taking an impression and is set, the impression tray is removed from the oral cavity of the patient in a state in which the set impression material is integrally held on the impression tray.
When taking such an impression from an edentulous patient (including a substantially edentulous patient), the impression must be taken from an alveolar ridge that forms a smooth curve. In this case, an extremely high accuracy is required, such as when pressing the impression material against the alveolar ridge with a uniform force.
For this reason, in order to more accurately take the intraoral impression, the impression is in many cases taken twice from the edentulous patient.
More particularly, a first impression is taken from the alveolar ridge by first using a general impression tray, and an edentulous jaw model is thereafter manufactured from the set impression material. Then, an impression tray (hereinafter referred to as a personal tray) exclusively for the edentulous patient is manufactured from the edentulous jaw model.
Next, the impression material is thinly applied on the personal tray, and a second impression is taken from the alveolar ridge, in order to manufacture a more accurate edentulous jaw model from the impression.
In the case of an edentulous patient, bite position and height must be determined separately because the edentulous patient has no teeth. Hence, a large number of processes, including measurements made from outside the face using a measuring apparatus and the like, determining the bite position and height by reflecting measured data to the edentulous jaw model on an articulator, and the like, are carried out in order to finally manufacture a full denture base.
As the impression tray for use in taking the impression from the edentulous patient, there is an impression tray for maxillary mucosa of the edentulous patient, applied with an utility wax, and including a peripheral wall part having an edge that makes contact with each mucosa at a bottom of a valley-shaped part between a cheek and a maxillary alveolar ridge of the patient having the edentulous alveolar ridge, and at an inner part of an maxillopalatine lower surface, a bottom plate part connected to a large portion of an edge on an opposite side from the edge of the peripheral wall part and provided with an impression material injection opening only at a part near the alveolar ridge at a front part of the peripheral wall part, and a handle provided on the front part of the peripheral wall part (refer to Patent Document 1, for example).
This impression tray for maxillary mucosa is for use in supplying and setting a slurry of a plaster impression material in order to take an accurate impression in a non-pressure state, and is applied with the utility wax so that the slurry of the impression material does not drop or leak from the impression tray (refer to paragraphs 0002-0005 of specification of Patent Document 1), and the impression only needs to be taken once.
However, this impression tray is merely for taking the impression of the alveolar ridge (refer to paragraph 0001 of specification of Patent Document 1), and no data can be obtained with respect to the bite position and height. For this reason, the full denture base cannot be manufactured by simply taking the impression using this impression tray, and as in the conventional case, the bite position and height must be determined through separate measurements and the like.